The joint shown is of two tubes of equal diameter. The same method works if joining a smaller tube to a larger one - the drill bit just needs to be the size of the larger tube (the one you are joining to), rather than the size of the tube being cut.
Have you considered a v-groove fixture, instead of the square channel? With proper clamping, it would hold the tube centred without the tight fit required by this setup, and would even work for various tubing diameters. The groove can be cut in a single pass with a suitable router bit.
Use water as coolant and up your rpm. It will keep the resin cool and provide a much cleaner cut. I have found. I learned that repairing 330 mph Funny Car bodies in under a hour between rounds🤦♂️ you can also use a thinner Kerf cutter. It will produce less heat via friction. Professional Marble, Granite, & Tile stores stock great Bits that don’t cost much more than your Milwaukee brand found at the Depot or Lowes. I do not know if or how surface RA effects joint bonding though? But I would like to🙏🏻
I think that it may be an improvement to use some sort of coolant while cutting with the abrasive bit. I have no experience with CF, but I know in the construction industry, we always try to use coolant on abrasive blades such as those. The other thing I could see being useful, is making a stair stepped jig that would be capable of accepting multiple tubing diameters. That's just my .02. Keep up the great work guys. I'm loving the videos.
The heat generated might damage the matrix at the point of contact by thermal degradation, but also pulling out fibers and introducing a delamination into the part.
Maybe a stupid question but would it be possible to make the darkaero 1 pressurised? And what about IFR? Love your design by the way. Keep up the good work boys.
Bjarki K thanks for the question - good question. The DarkAero 1 is optimized w/ best performance from 8,000 to 12,000 feet where pressurization isn’t needed. We don’t plan to do pressurization due to the weight and complexity. The aircraft is IFR capable and the instrument panel is large enough to install a full IFR system.
For more composites related knowledge check out: www.darkaero.com/knowledge/composites/ Want even more? We also offer consulting: www.darkaero.com/consulting
hello , have you made the video to show how connnect the tubes togeter after made that work of preparation ? i have made a T and a elbow with carbon tube , i need it become very resistant , thanks
If you put painter's tape at the end of the tube would you get a cleaner finish on the bottom of the tube where the bit breaks thru to prevent "breakout"?
Dominic, thank you for watching and the comment! Yes, that would be a nice addition to the shop. Our space is a little limited at the moment so it would be challenging to fit one in. We would like to have a few of these for when we get into production.
@@DarkAeroInc Might I suggest building the small homebuilder version from EAA? Even that will be miles better for your builders when "deburring" and possibly even adapted into your tube holding jig: www.eaa.org/Videos/Hints-for-Homebuilders/Tools-and-Workshop/77813814001
Measure the thickness of some 400 or 800 grit and paper, produce a 8 or 12" long carbon fiber tube/mandrel 0.75" in diameter minus the thickness of one layer of sandpaper you choose. When the sand paper is applied to the mandrel in a single layer it is exactly 0.7500" then sand the cut made by the diamond bit or other cutting technology to have a perfect fit to bond the two surfaces. You could even speed things up by chucking the mandrel into the drill press similar to using a drum sander except this is made to give you the exact fit you need without a gap in your joint.
I would be interested is seeing how you join the carbon fiber tubes together. (Hardware, epoxy?) Thanks for sharing.
Jay Schweitzer we are working on another video that covers that. :)
Yup I want to see that too and would love to know the strength of that joint compared to traditional chromoly of the same diameter.
@@DarkAeroInc when
@@DarkAeroInc Same question how you fix those notched tube together? Thanks
The joint shown is of two tubes of equal diameter. The same method works if joining a smaller tube to a larger one - the drill bit just needs to be the size of the larger tube (the one you are joining to), rather than the size of the tube being cut.
Have you considered a v-groove fixture, instead of the square channel? With proper clamping, it would hold the tube centred without the tight fit required by this setup, and would even work for various tubing diameters. The groove can be cut in a single pass with a suitable router bit.
Also, I enjoy how you put the shop vac hose on the side of the bit where the majority of the dust comes out (clockwise in this case).
Use water as coolant and up your rpm. It will keep the resin cool and provide a much cleaner cut. I have found. I learned that repairing 330 mph Funny Car bodies in under a hour between rounds🤦♂️ you can also use a thinner Kerf cutter. It will produce less heat via friction. Professional Marble, Granite, & Tile stores stock great Bits that don’t cost much more than your Milwaukee brand found at the Depot or Lowes. I do not know if or how surface RA effects joint bonding though? But I would like to🙏🏻
I'd be interested in trying to build a tailwind W10 fuselage with carbon tubes!
I know it's been a while. Is that pulltruded tube or what is that?
I saw torx screws good on you. Phillips is so bad
What kind of glue do you use for the joints?
Cooling with water is good for the tools, the carbon and easier cleaning.
Water does keep the dust down! Any tips for implementing this in a simple setup? Just get the tube and the cutting tool wet?
@@DarkAeroInc A long box with the jig/tube inside clamped to the drill table,
An oven tray for small stuff
So you did 90 degree angle cut how about a 45 degree cut?
Basically, you tilt the drill press table to the desired angle.
I think that it may be an improvement to use some sort of coolant while cutting with the abrasive bit. I have no experience with CF, but I know in the construction industry, we always try to use coolant on abrasive blades such as those. The other thing I could see being useful, is making a stair stepped jig that would be capable of accepting multiple tubing diameters. That's just my .02. Keep up the great work guys. I'm loving the videos.
The heat generated might damage the matrix at the point of contact by thermal degradation, but also pulling out fibers and introducing a delamination into the part.
Maybe a stupid question but would it be possible to make the darkaero 1 pressurised? And what about IFR? Love your design by the way. Keep up the good work boys.
Bjarki K thanks for the question - good question. The DarkAero 1 is optimized w/ best performance from 8,000 to 12,000 feet where pressurization isn’t needed. We don’t plan to do pressurization due to the weight and complexity. The aircraft is IFR capable and the instrument panel is large enough to install a full IFR system.
What are the limiting factors ( besides money) keeping someone from building a tube and fabric aircraft with carbon tubing instead of chromoly steel?
Steel will bend. Carbon breaks.
For more composites related knowledge check out: www.darkaero.com/knowledge/composites/
Want even more? We also offer consulting: www.darkaero.com/consulting
How strong are these joints once complete? Can they be used in actual structural applications? Like for homebuilt aircraft structure?
Yes if you use a structural bonding agent
hello , have you made the video to show how connnect the tubes togeter after made that work of preparation ? i have made a T and a elbow with carbon tube , i need it become very resistant , thanks
If you put painter's tape at the end of the tube would you get a cleaner finish on the bottom of the tube where the bit breaks thru to prevent "breakout"?
Your tube holder is way off. Ever heard of a v block? That's all you need to cut round materials like that.
Carbon fibre stealth bridges placed by 8 chinooks over Narada ready in a day to allow rail and road traffic to pass in seconds.
How do you join the tubes?
0:13 It's also called a fishmouth.
How to join these
Good info
Shop vac exhaust probably should to outside
did you see it inside? or is this just a common sense guide comment? I know I vent my shop vac to the exterior when situations warrant it.
Have you guys considered buying a downdraft table for all the sanding work you do ?
Dominic, thank you for watching and the comment! Yes, that would be a nice addition to the shop. Our space is a little limited at the moment so it would be challenging to fit one in. We would like to have a few of these for when we get into production.
@@DarkAeroInc Might I suggest building the small homebuilder version from EAA? Even that will be miles better for your builders when "deburring" and possibly even adapted into your tube holding jig: www.eaa.org/Videos/Hints-for-Homebuilders/Tools-and-Workshop/77813814001
@@michaeldunning7471 why link a members only video?
Measure the thickness of some 400 or 800 grit and paper, produce a 8 or 12" long carbon fiber tube/mandrel 0.75" in diameter minus the thickness of one layer of sandpaper you choose. When the sand paper is applied to the mandrel in a single layer it is exactly 0.7500" then sand the cut made by the diamond bit or other cutting technology to have a perfect fit to bond the two surfaces. You could even speed things up by chucking the mandrel into the drill press similar to using a drum sander except this is made to give you the exact fit you need without a gap in your joint.
thanks for the clear guide!
Yeah forstner bits WOOOOOOOT
you glue them together? or other way?
that looks like the easy part...but how the hell do you bond them together?
Thanks for watching! We have a video on that. Check out: ua-cam.com/video/d4riggc3IZk/v-deo.html